Shania Twain is "tired of suppressing [herself]" when it comes to talking about the unraveling of her marriage and betrayal at the hands of her best friend. In the June issue of REDBOOK, Twain, 45, candidly speaks about the breakup of her 14-year-marriage to music producer Robert "Mutt" Lange after his affair with her close friend Marie-Anne Thiebaud.

"I felt that the sooner I could relax about my secrets, the sooner I'd find the relief that comes with release," she explains. "Nothing like getting it out there in the sunshine and fresh air."

So just what did it feel like when she found out about her former best friend and ex-husband's affair? "It was like I was kicked off my own bus while it was moving full speed ahead, and I landed in the dirt and everything I had was thrown out after me. And after tumbling and getting a mouthful of dirt, I had to try to stand up, then figure out where I was and start walking."

Twain says it took about eight months before she realized, "Yes, I'm still me, and yes, I'm a mother, and yes, I'm a singer and a songwriter, and I can love again, and I have friends, and yes, I'm alive."

The five-time Grammy winner was unable to sing in front of people after the affair because of a condition called dysphonia. "It's a constriction that's both psychological and emotional, and it literally does choke the muscles around the voice box."

"When my marriage broke down, I got so physically constricted that I couldn't get any volume out at all," she recalls. "I couldn't even call for my dog. I realize I couldn't live without singing and had to do something about it. This is why I was like, 'Just get it all out right now. Clean the pipes.'"

Twain's now-husband, FredericThiebaud, understood exactly how she was feeling. It was Thiebaud's ex-wife who had an extramarital affair with Twain's ex. "I got to observe Fred going through the same thing that I was, and I admired how he handled it," she explains. "That is where I fell in love with him, because he was so exemplary in every way."